I have noticed, for example, the more I train with a yawara (small stick), the more I transfer these same techniques to my weaponless defenses (for nerve point attacks I often use a knuckle in place of the stick). It works as well with longer weapons such as a Bo staff where leg kicks can be substituted for many of the sweeps/attacks.
The bottom line is that we are always training to hit the same joints and vulnerable areas of the body regardless of what we have or do not have in our hand.
This is not to say a weapon will not be more devastating if it connects (a bullet's speed beats a straight punch any day--and a knife is sharper than a ridge hand strike), but in the end, we can use our hands and feet to emulate such attacks.
And vice vera, of course.